Zac Swindells, the chief executive of collapsed Telstra reseller ispONE, has called for tougher regulation on Australia’s largest mobile networks, warning low-cost competitors could be squeezed out of the industry.

He said that left unchecked Australia’s largest carriers Telstra, Optus and Vodafone could close their networks to low-cost competitors in a bid to directly control customers.

“All you need to look at is the Telstra’s numbers and their market penetration has reached a point where serious questions have to be raised,” he told The Australian Financial Review.

“Whilst it’s an unregulated product, the [mobile virtual network operator] market will suffer to some degree if they can’t procure supply.”

ispONE, which resold access to Telstra’s 3G mobile network to mobile services operated by ALDI and Kogan, appointed administrators in August after a failed legal bid against Telstra.

Though ALDI customers signed a last-minute deal with Telstra to retain customers on the network, those who had purchased Kogan Mobile’s prepaid products – sometimes up to 12 months in advance – were forced to find new mobile carriers.

Corporate administrators Ferrier Hodgson completed a sale on Monday of parts of ispONE, including its billing platform, mobile subsidiaries and more than 61,000 customers, to Melbourne-based Conec2.